Three-dimensional shaping method

ABSTRACT

A three-dimensional object that maintains a satisfactory visual color quality when the object is observed at different positions or through different angles, and a three-dimensional shaping apparatus for and a three-dimensional shaping method of shaping such a three-dimensional object are provided. The three-dimensional object includes: a shaping base having a first and second outer surfaces adjacent to each other at an adjacent angle; a first colored layer formed on the first outer surface and including a transparent material colored in a first color; a second colored layer formed on the second outer surface and including a transparent material colored in a second color different from the first color; and a partition layer interposed between the side surfaces of the first colored layer and the second colored layer. The partition layer is opaque and has one of the first color, the second color, and an achromatic color.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 15/372,403, filed on Dec. 8, 2016, which claims the prioritybenefit of Japanese Patent Application No. 2015-241803, filed on Dec.11, 2015. The entirety of the above-mentioned patent application ishereby incorporated by reference herein and made a part of thisspecification.

BACKGROUND Technical Field

This disclosure relates to a three-dimensional object colored on atleast outermost surfaces thereof, and a three-dimensional shapingapparatus for and a three-dimensional shaping method of shaping such athree-dimensional object.

Related Art

In recent times, three-dimensional shaping apparatuses have beendeveloped (generally called, 3D printers). These apparatuses areconfigured to shape a three-dimensional object by stacking slices of amaterial in layers (hereinafter, unit layers) while solidifying thematerial per slice. Thus far have been disclosed various techniques forcoloring the outermost surfaces of such a shaped object.

Japanese Unexamined Patent Publication No. 2000-280256 ([0055], andFIGS. 4A to 4D describes a three-dimensional shaping apparatus equippedwith nozzles for shaping and coloring. A resin to be shaped isdischarged through the shaping nozzle, and colorants having differentcolors are discharged through the coloring nozzles. This literaturefurther describes a three-dimensional object in which a colored regionis formed on the inner side by a predetermined width with respect to theoutermost surfaces to avoid exposure of any inner uncolored portion.

SUMMARY

The inventors of this application have found the following fact throughtheir studies. When an observer looks at a three-dimensional object fromthe side of an outermost surface having a color, another color of adifferent outermost surface is possibly mixed with the color and thenperceived by the observer's eye. Such color mixture may attract theobserver's attention particularly when he/she looks at the vicinity ofan apex defined by two outermost surfaces, because the path length oflight passing through the three-dimensional object is relatively shortin the apex vicinity, inviting the observer to simultaneously perceivecolor components of the different outermost surfaces.

However, Japanese Unexamined Patent Publication No. 2000-280256 ([0055],and FIGS. 4A to 4D is totally silent about the color mixture and theresulting issue. The observer, looking at the three-dimensional objectdescribed in Japanese Unexamined Patent Publication No. 2000-280256([0055], and FIGS. 4A to 4D, may feel uncomfortable with local colordifferences on the outermost surfaces of this object.

To address the issue, this disclosure is directed at providing athree-dimensional object that maintains a satisfactory visual colorquality when the object is observed at different positions or throughdifferent angles, and a three-dimensional shaping apparatus for and athree-dimensional shaping method of shaping such a three-dimensionalobject.

“A three-dimensional object” disclosed herein includes: a shaping basehaving a first outer surface and a second outer surface adjacent to eachother at an adjacent angle; a first colored layer formed on the firstouter surface of the shaping base, the first colored layer including atransparent material colored in a first color; a second colored layerformed on the second outer surface of the shaping base, the secondcolored layer including a transparent material colored in a second colordifferent from the first color; and a partition layer interposed betweena side surface of the first colored layer and a side surface of thesecond colored layer, the partition layer being opaque and having one ofthe first color, the second color, and an achromatic color.

By interposing the opaque partition layer having the achromatic orsecond color between the side surfaces of the first colored layer andthe second colored layer, incident light through the first colored layerfrom the outside of the three-dimensional object may be less likely totransmit through or prevented from transmitting through the secondcolored layer and exiting from the object. Further, incident lightthrough the second colored layer from the outside may be reflected fromthe partition layer having a substantially uniform spectral reflectancewithin a visible light region or a spectral reflectance similar to thatof the second colored layer. This may deliver a light-shielding effectthat prevents perception of color components of the first colored layerand/or partition layer when an observer looks at the second coloredlayer of the three-dimensional object. As a result, the object maymaintain a satisfactory visual color quality when observed at differentpositions or through different angles. The object may likewise maintaina satisfactory visual color quality as per the same principle when thefirst colored layer of the three-dimensional object is observed.

Preferably, the side surface of the first colored layer makes a surfacecontact with the side surface of the second colored layer at a contactportion on an outer side in a thickness direction, and the partitionlayer is disposed on an inner side in the thickness direction withrespect to the contact portion. This may prevent exposure of thepartition layer that differ in color from the first colored layer or thesecond colored layer, allowing the three-dimensional object to maintaina satisfactory visual appearance.

Preferably, the partition layer has a lower light transmittance than thefirst colored layer and the second colored layer. This may increase thelight-shielding effect exerted by the partition layer.

Preferably, the partition layer has a higher light transmittance as theadjacent angle has a greater degree. Greater adjacent angles areinclined to conduce to a greater range of angles through which thepartition layer is visible from the outside (hereinafter, visibilityangle). In the light of this fact, the light transmittance of thepartition layer may be increased with greater degrees of the adjacentangle. This may decrease the quantity of light reflected from thesurface of the partition layer, consequently making the partition layerbarely visually recognizable from the outside of the three-dimensionalobject.

Preferably, the partition layer is provided only where the adjacentangle has a degree less than a threshold. Greater adjacent angles may beprone to the following two outcomes; longer path length of lighttraversing the apex vicinity of the three-dimensional object, andgreater visibility angles of the partition layer. Taking these possibleoutcomes into consideration, the partition layer possibly visible fromthe outside may be omitted, if unneeded. This may prevent that thethree-dimensional object is degraded in visual appearance on thecontrary to expectation.

Preferably, the first outer surface and the second outer surface have anopaque achromatic color. This may allow the first colored layer and thesecond colored layer to exhibit their colors as desired when thesecolored layers are observed from the outer periphery of the shapingbase.

“A three-dimensional shaping apparatus” disclosed herein is configuredto shape a three-dimensional object by vertically stacking unit layerson one another that includes a plurality of different shaping materialsthat enable color reproduction of at least a first color and a secondcolor different from the first color. The three-dimensional objectshaped includes: a shaping base having a first outer surface and asecond outer surface adjacent to each other at an adjacent angle; afirst colored layer formed on the first outer surface of the shapingbase, the first colored layer including a transparent material coloredin the first color; and a second colored layer formed on the secondouter surface of the shaping base, the second colored layer including atransparent material colored in the second color. The apparatus has: adata obtaining unit that obtains color shaping data representing anoriginal colored object including the shaping base, the first coloredlayer, and the second colored layer; and a data correcting unit thatcorrects the color shaping data obtained by the data obtaining unit tointerpose a partition layer between a side surface of the first coloredlayer and a side surface of the second colored layer in the originalcolored object, the partition layer being opaque and having one of thefirst color, the second color, and an achromatic color.

“A three-dimensional shaping method” is a method of shaping athree-dimensional object by stacking unit layers on one another using athree-dimensional shaping apparatus, the unit layers including aplurality of different shaping materials that enable color reproductionof at least a first color and a second color different from the firstcolor. The three-dimensional object includes: a shaping base having afirst outer surface and a second outer surface adjacent to each other atan adjacent angle; a first colored layer formed on the first outersurface of the shaping base, the first colored layer including atransparent material colored in the first color; and a second coloredlayer formed on the second outer surface of the shaping base, the secondcolored layer including a transparent material colored in the secondcolor. The method includes: an obtaining step of obtaining color shapingdata representing an original colored object including the shaping base,the first colored layer, and the second colored layer; and a correctingstep of correcting the color shaping data obtained in the obtaining stepto interpose a partition layer between a side surface of the firstcolored layer and a side surface of the second colored layer in theoriginal colored object, the partition layer being opaque and having oneof the first color, the second color, and an achromatic color.

The three-dimensional object disclosed herein may maintain asatisfactory visual color quality when observed at different positionsor through different angles. The three-dimensional shaping apparatus andthe three-dimensional shaping method disclosed herein may successfullyshape such a three-dimensional object.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a three-dimensional object according toan embodiment of the present disclosure;

FIG. 2 is an enlarged cross-sectional view taken along II-II line inFIG. 1; FIG. 3 is a schematic perspective view of the three-dimensionalobject illustrated in FIG. 1;

FIGS. 4A and 4B are schematic explanatory drawings of visual features ofthe three-dimensional object illustrated in FIGS. 1 to 3;

FIGS. 5A and 5B are drawings of the whole structure of athree-dimensional shaping apparatus used to shape the three-dimensionalobject illustrated in FIG. 1;

FIG. 6 is a block diagram of the apparatus illustrated in FIG. 5A andFIG. 5B;

FIG. 7 is an operational flow chart of the three-dimensional shapingapparatus illustrated in FIG. 5A and FIG. 5B;

FIG. 8 is a schematic drawing, illustrating how to decide the positionof a partition layer; and

FIGS. 9A and 9B are schematic drawings, illustrating how to correctcolor shaping data.

DETAILED DESCRIPTION

Hereinafter are described embodiments of a three-dimensional objectdisclosed herein referring to the accompanying drawings in connectionwith a three-dimensional shaping apparatus and a three-dimensionalshaping method.

[Description of Three-Dimensional Object 10] 1. Structure ofThree-Dimensional Object 10

FIG. 1 is a perspective view of a three-dimensional object 10 accordingto an embodiment of this disclosure. FIG. 2 is an enlargedcross-sectional view taken along II-II line in FIG. 1. FIG. 3 is aschematic perspective view of the three-dimensional object 10illustrated in FIG. 1.

As illustrated in FIG. 1, the three-dimensional object 10 is an objecthaving a shape with an aspect ratio slightly changed from that of aregular octahedron. This object has four outermost surfaces 12 in theshape of an equilateral triangle. These outermost surfaces 12 arecolored in a first color (for example, red). This object further hasfour outermost surfaces 14 in the shape of an equilateral triangle.These outermost surfaces 14 are colored in a second color different fromthe first color (for example, blue). Thus, the three-dimensional object10 is decorated in two colors; red and blue, so as to have its adjacentoutermost surfaces 12 and 14 differ in color.

As illustrated in FIG. 2, the three-dimensional object 10 includes ashaping base 16 as its base, one or a plurality of first colored layers20 formed on one or a plurality of first outer surfaces 18, one or aplurality of second colored layers 24 formed on one or a plurality ofsecond outer surfaces 22, and a partition layer(s) 26 interposed betweenthe first and second colored layers 20 and 24. Both or either one of thefirst and second outer surfaces 18 and 22 may be a flat surface or acurved surface.

The shaping base 16, first colored layers 20, second colored layers 24,and partition layers 26 are made of a material curable through aphysical treatment or a chemical treatment. Examples of the material mayinclude photo-curable resins and thermosetting resins. In case of usingan ultraviolet-curable resin cured by being irradiated with ultraviolet(UV) light, examples of such a resin may include radical polymerizationUV-curable resins cured by initiating radical polymerization reactions,and cationic polymerization UV-curable resins cured by initiatingcationic polymerization reactions. Examples of the radicalpolymerization UV-curable resins may include urethane acrylate, acrylicacrylate, and epoxy acrylate.

The shape of the shaping base 16 is substantially a regular octahedronsimilarly to the three-dimensional object 10. The shaping base 16 hasfour sets of first outer surfaces 18 and second outer surfaces 22respectively adjacent to each other at an adjacent angle θ. At least thefirst outer surfaces 18 and the second outer surfaces 22 of the shapingbase 16 are colored in a color or made of a material that differ fromthe colors or materials of the first and second colored layers 20 and24. The first outer surfaces 18 and the second outer surfaces 22 maypreferably have an opaque achromatic color or white color. This mayallow the first colored layers 20 and the second colored layers 24 toexhibit their colors as desired when these colored layers are observedfrom the outer periphery of the shaping base 16.

The “opaque” means no transparency to light, and more particularly meansthat “the total luminous transmittance of plastics” set forth in JISK7375: 2008 is less than or equal to 20% (optical density of 0.7 D ormore). The “achromatic” means “achromatic as strictly defined” with zerosaturation (S) in the HLS color system, and may further mean “substantially achromatic” with very low saturation (substantially 10% orless).

The first colored layer 20 includes a transparent material colored inthe first color and covers the whole of the corresponding first outersurface 18 in a certain thickness. The second colored layer 24 includesa transparent material colored in the second color and covers the wholeof the corresponding second outer surface 22 in a certain thickness. Ina case where the shaping base 16 has an adequately large size, thethicknesses of the first colored layer 20 and the second colored layer24 may range from 50 to 1,000 μm, and may preferably range from 200 to500 μm.

The side surface of the first colored layer 20 makes a surface contactwith the side surface of the adjacent second colored layer 24 at acontact portion 28 closer to the outermost surface 12 (outer side in thethickness direction). The partition layer 26 integral with the shapingbase 16 is disposed at a position closer to the first outer surface 18with respect to the contact portion 28 (inner side in the thicknessdirection). The partition layer 26 has an opaque achromatic color, forexample, a white color like the shaping base 16.

The partition layer 26 is made of a material having a relatively lowlight transmittance. The partition layer 26 has, therefore, a lowerlight transmittance than the first colored layer 20 and the secondcolored layer 24. The partition layer 26 has a relatively largethickness. This, in addition to or apart from the material used, maylower the light transmittance of the partition layer 26 as compared tothe first colored layer 20 and the second colored layer 24.

As illustrated in FIG. 3, four partition layers 26 are formed alongridges 30 of the three-dimensional object 10 (illustrated with two-dotlines) on the slightly inner side of the ridges 30. The partition layer26 is formed in a band-like shape having a certain width and is bent ina substantially L shape at an intermediate position in a lengthwisedirection thereof. The four partition layers 26 are connected to oneanother at one ends and the other ends thereof.

References signs Q1, Q2, Q3, and Q4 respectively refer to apexesadjacent to an apex P. Then, an adjacent angle θ between a plane Q1PQ2constituting the outermost surface 12 and a plane Q1PQ3 constituting theoutermost surface 14 is 90 degrees (θ=90 degrees), and an adjacent angleθ between the plane Q1PQ2 constituting the outermost surface 12 and aplane Q3PQ4 constituting the outermost surface 14 is 120 degrees (θ=120degrees).

The partition layer 26 is provided in accordance with the magnitude ofthe adjacent angle θ relative to a threshold θth (for example, 100degrees). Specifically, the partition layer 26 is provided in vicinityof the ridges 30 (side PQ1, side PQ4) having the adjacent angle θ of 90degrees, whereas the partition layer 26 is not provided in vicinity ofthe ridges 30 (side PQ2, side PQ3) having the adjacent angle θ of 120degrees. Stated differently, the partition layer 26 is provided onlywhere the adjacent angle θ has a degree less than the threshold θth.

2. Visual Features of Three-Dimensional Object 10

The three-dimensional object 10 according to this embodiment isstructured as described above. The visual features of thethree-dimensional object 10 illustrated in FIGS. 1 to 3 are hereinafterdescribed referring to FIGS. 4A and 4B.

FIG. 4A is a schematic drawing, illustrating an optical phenomenon whenan apex of an object having no partition layer 26 (conventionalthree-dimensional object) is observed from an outermost surface 14 sidethereof. The observer perceives the color and the shape of this objectbased on the position distribution and spectral characteristics ofnatural light 34 received by an eye 32. For example, the natural light34 entering through the outermost surface 14 is reflected from theoutermost surface 14 or the contact portion 28, and then received as areflected component 36 containing blue light in abundance.

In the meantime, optical paths traversing apexes or their vicinity areshorter than in any other portions. Further, the optical paths do nottraverse the shaping base 16 having opacity (no transparency to light).The natural light 34 entering through the second colored layer 24 may bereflected from the contact portion 28 having an ununiform spectralreflectance within a visible light region. The reflected light may thenbe received as a reflected component 36 containing relatively less bluelight. The natural light 34 entering through the outermost surface 12may transmit through the first colored layer 20 and then transmitthrough the second colored layer 24. The transmitted light may then bereceived as a transmitted component 38 containing green light inabundance.

When the object thus positioned is observed from the outermost surface14 side, the color of the outermost surface 12 may be mixed with thecolor of the outermost surface 14 and then perceived by the observer'seye. Specifically, the observer may perceive “blue color” in a regionthat has received the reflected component 36 alone, while perceiving“bluish green color” in a region that has received the reflectedcomponent 36 and the transmitted component 38 simultaneously. As aresult, the observer may feel uncomfortable with such a local colordifference on the outermost surface 14.

FIG. 4B is a schematic drawing, illustrating an optical phenomenon whenan apex of the three-dimensional object 10 having the partition layers26 is observed from an outermost surface 14 side thereof. Similarly tothe object illustrated in FIG. 4A, the natural light 34 entering throughthe outermost surface 14 is received as the reflected component 36containing blue light in abundance.

As is known from the drawing, the object 10 has the opaque achromaticpartition layer 26 interposed between the optical paths traversing theapex or its vicinity. The natural light 34 entering through the secondcolored layer 24 may be reflected from the partition layer 26 having asubstantially uniform spectral reflectance within a visible lightregion. The reflected light may then be received as the transmittedcomponent 38 containing blue light in abundance. The natural light 34entering through the outermost surface 12 may transmit through the firstcolored layer 20; however, the transmitted light may be entirely ormostly reflected from the partition layer 26.

This may deliver a light-shielding effect that prevents perception ofcolor components of the first colored layer 20 and the partition layer26 at the time of observing the second colored layer 24 of thethree-dimensional object 10. Likewise, a light-shielding effect may bedelivered that prevents perception of color components of the secondcolored layer 24 and the partition layer 26 at the time of observing thefirst colored layer 20 of the three-dimensional object 10. In this way,regardless of whether the observer is gazing at any one of the apexes,the whole region of the first colored layer 20 may appear “red”, and thewhole region of the second colored layer 24 may appear “blue” to theobserver's eye.

3. Effects Attained by Three-Dimensional Object 10

As described so far, the three-dimensional object 10 includes: theshaping base 16 having the first outer surface(s) 18 and the secondouter surface(s) 22 adjacent to each other at the adjacent angle θ; thefirst colored layer(s) 20 formed on the first outer surface(s) 18 of theshaping base 16 and including a transparent material colored in thefirst color; the second colored layer(s) 24 formed on the second outersurface 22 of the shaping base 16 and including a transparent materialcolored in the second color different from the first color; and thepartition layer 26 interposed between the side surfaces of the first andsecond colored layers 20 and 24. The partition layer 26 is opaque andhas an achromatic color with zero saturation or very low saturation.

By interposing the opaque achromatic partition layer 26 between the sidesurfaces of the first colored layer 20 and the second colored layer 24,the natural light 34 entering through the first colored layer 20 fromthe outside of the three-dimensional object 10 may be less likely totransmit through or prevented from transmitting through the secondcolored layer 24 and exiting from the object. Further, the natural lightentering through the second colored layer 24 from the outside may bereflected from the partition layer 26 having a substantially uniformspectral reflectance within a visible light region. Then, thelight-shielding effect thereby delivered prevents perception of colorcomponents of the first colored layer 20 and the partition layer 26 atthe time of observing the second colored layer 24 of thethree-dimensional object 10. As a result, the object 10 may maintain asatisfactory visual color quality when observed at different positionsor through different angles. When the first colored layer 20 of thethree-dimensional object 10 is observed, the object may likewisemaintain a satisfactory visual color quality as per the same principle.

The side surface of the first colored layer 20 may make a surfacecontact with the side surface of the second colored layer 24 at thecontact portion 28 on the outer side in the thickness direction, and thepartition layer 26 may be disposed on the inner side in the thicknessdirection with respect to the contact portion 28. This may preventexposure of the partition layer 26 that differ in color from the firstcolored layer 20 or the second colored layer 24, allowing thethree-dimensional object 10 to maintain a satisfactory visualappearance.

Preferably, the partition layer 26 has a lower light transmittance thanthe first colored layer 20 and the second colored layer 24. This mayincrease the light-shielding effect exerted by the partition layer 26.

The partition layer 26 may be provided only where the adjacent angle θhas a degree less than the threshold 0th. Greater degrees of theadjacent angle 0 may be prone to the following two outcomes; longer pathlength of light traversing the apex vicinity of the three-dimensionalobject 10, and a greater range of angles through which the partitionlayer 26 is visible from the outside (hereinafter, visibility angle).Taking these possible outcomes into consideration, the partition layer26 visually recognizable from the outside may be omitted, if unneeded.This may prevent that the three-dimensional object 10 is degraded invisual appearance on the contrary to expectation.

4. Modified Example

The three-dimensional object 10 is not necessarily limited to thedescribed example. It should be understood that the object 10 may havean optional shape, color, or pattern. The partition layer 26 may bevariously modified to effectively improve the light-shielding effect.

[1] For example, the partition layer 26 may have a color other thanwhite, gray, black, and an achromatic color close to white, gray, orblack. The partition layer 26 may have one of the first color and thesecond color. In a case where partition layer 26 having the first coloris provided, the natural light 34 entering through the first coloredlayer 20 may be reflected from the partition layer 26 having a spectralreflectance similar to that of the second colored layer 24 and thenreceived as the reflected component 36 containing color components ofthe first color in abundance. The partition layer 26 colored in thefirst color (or second color) may be unlikely to adversely affect colorreproducibility of the first colored layer 20 (or second colored layer24).

This may deliver a light-shielding effect that prevents perception ofcolor components of the second colored layer 24 at the time of observingthe first colored layer 20 of the three-dimensional object 10. As aresult, the object 10 may maintain a satisfactory visual color qualitywhen observed at different positions or through different angles. In acase where the partition layer 26 having the second color is provided,the three-dimensional object 10 may likewise maintain a satisfactoryvisual color quality as per the same principle at the time of observingthe second colored layer 24 of this object.

[2] Even in a case of the adjacent angle 0 greater than or equal to θth(0≥0th), the partition layer 26 may be interposed between the sidesurfaces of the first colored layer 20 and the second colored layer 24.Greater adjacent angles are inclined to conduce to a greater range ofvisibility angles of the partition layer 26. In the light of this fact,the partition layer 26 may have a higher light transmittance withgreater degrees of the adjacent angle θ. This may decrease the quantityof light reflected from the surface of the partition layer 26,consequently making the partition layer 26 barely visually recognizablefrom the outside of the three-dimensional object 10.

[Description of Three-Dimensional Shaping Apparatus 100]

A three-dimensional shaping apparatus 100 used to form thethree-dimensional object 10 is hereinafter described referring to FIGS.5A to 9.

1. Description of Principal Structural Elements

FIGS. 5A and 5B are schematic drawings of structural elements of thethree-dimensional shaping apparatus 100 according to the embodiment.FIG. 5A is a schematic side view of the three-dimensional shapingapparatus 100. FIG. 5B is a schematic plan view of the three-dimensionalshaping apparatus 100. These drawings illustrate a multilayeredstructure 50 constituting the three-dimensional object 10 currentlyshaped.

The multilayered structure 50 includes a modeling material 52 (shapingmaterial) that is the raw material of the three-dimensional object 10,and a support material 54 that supports the modeling material 52 fromits outer or inner side. The multilayered structure 50 is formed of unitlayers including the modeling material 52 and/or support material 54 andvertically stacked on one another. In the description below, theuppermost surface of the multilayered structure 50 may be referred to as“unit layer surface 56”.

The three-dimensional shaping apparatus 100 includes a mounting unit 60on which the multilayered structure 50 is to be mounted, a carriage 62loaded with a mechanism for discharging the modeling material 52 and thesupport material 54, and a carriage driving unit 64 that drives thecarriage 62 to move in X and Y directions.

The mounting unit 60 has a mounting table 68 with a flat work surface66, and a stage driver 70 that drives the mounting table 68 to move inthe normal direction (Z direction) of the work surface 66. The carriagedriving unit 64 has a pair of guide rails 72, 72 (X bars) extending inparallel to the X direction, two sliders 74, 74 movable along therespective guide rails 72, and a carriage rail 76 (Y bar) hanging acrossthe two sliders 74, 74 and extending in the Y direction.

The carriage 62 is attached to the carriage rail 76. The carriage 62 ismovable along the carriage rail 76 or movable as a unit with thecarriage rail 76 along the guide rails 72, 72. This may allow forrelative movements of the carriage 62 and the mounting table 68 in the Xdirection, Y direction, and Z direction intersecting one another. Inthis embodiment, the X direction and the Y direction are coincident withthe “horizontal direction”, and the Z direction is coincident with the“vertical direction”. These three directions are orthogonal to oneanother.

The carriage 62 is mounted with a discharge unit 80, a flattening roller82, and a curing unit 84. The discharge unit 80 discharges the modelingmaterial 52 and the support material 54 both having fluidity(hereinafter, may be collectively referred to as “droplets 78”) to thework surface 66. The flattening roller 82 flattens the unit layersurface 56. The curing unit 84 cures the droplets 78 on the unit layersurface 56.

The discharge unit 80 includes discharge surfaces 86 and is located soas to have the discharge surfaces 86 face the work surface 66 or theunit layer surface 56. The discharge unit 80 has a plurality ofdischarge heads 88 that discharge the modeling material 52 in the samecolor or different colors, and one discharge head 90 that discharges thesupport material 54. Various techniques are available for the mechanismemployed to discharge the droplets 78 from the discharge heads 88 and90. For instance, an actuator including a piezoelectric element may bemodified for the discharge of the droplets 78. The modeling material 52or the support material 54 may be heated by a heater (heat generator) togenerate air bubbles, so that the droplets 78 are discharged under thepressure of the generated air bubbles.

The discharge heads 88 and 90 have, on their discharge surfaces 86,nozzle arrays 94 each having a plurality of nozzles 92 aligned in a rowin the lengthwise direction of the nozzle array (X direction in thedrawing). In a case where the discharge unit 80 has six discharge heads88, the six discharge heads 88 respectively discharge the droplets 78 ofthe modeling material 52 colored in cyan (C), magenta (M), yellow (Y),black (K), clear (CL), and white (W) colors, for example.

The curing unit 84 is a device that cures the droplets 78 of themodeling material 52 by applying a form of energy to the droplets 78.The curing unit 84 is operable to apply various forms of energy. When anultraviolet-curable resin is used as the modeling material 52, thecuring unit 84 is equipped with an ultraviolet light source thatradiates ultraviolet light as light energy. When a thermosetting resinis used as the modeling material 52, the curing unit 84 is equipped witha heating device that applies heat energy, and, if necessary, a coolingdevice for cooling the multilayered structure 50.

Examples of the ultraviolet light source may include rare gas dischargelamps, mercury discharge lamps, fluorescent lamps, and LED (lightemitting diode) arrays. The support material 54 may be selected frommaterials that can be removed without altering the properties of thethree-dimensional object 10, examples of which may includewater-swelling gels, waxes, thermoplastic resins, water-solublematerials, and soluble materials.

2. Block Diagram

FIG. 6 is a block diagram of the three-dimensional shaping apparatus 100according to the embodiment. The three-dimensional shaping apparatus 100includes, in addition to the carriage driving unit 64, stage driver 70,discharge unit 80, and curing unit 84 illustrated in FIGS. 5A and 5B, acontroller 102, an image input I/F 104, an input unit 106, an outputunit 108, a storage 110, a three-dimensional driving unit 112, and adriver circuit 114.

The image input I/F 104 includes a serial I/F, a parallel I/F, a USBI/F, or an Ethernet (registered trademark) I/F. The image input I/F 104receives electric signals containing image information representing thethree-dimensional object 10 from an external apparatus not illustratedin the drawing. The input unit 106 includes a mouse, a keyboard, a touchsensor and/or a microphone. The output unit 108 includes a displayand/or a speaker.

The storage 110 is a non-transitory storage and includes acomputer-readable storage medium. Examples of the computer-readablestorage medium may include transportable media, for example,magneto-optical discs, ROM, CD-ROM, flash memories, and storage devicessuch as a hard disc mounted in a computer system. The storage mediumused may be configured to dynamically store programs for a brief periodof time or store programs for a certain period of time.

The three-dimensional driving unit 112, by driving at least one of themounting table 68 and the discharge unit 80, three-dimensionally movesthe discharge unit 80 relative to the mounting table 68. In thisembodiment, the three-dimensional driving unit 112 includes the carriagedriving unit 64 that drives the discharge unit 80 to move in the X and Ydirections, and the stage driver 70 that drives the mounting table 68 tomove in the Z direction.

The controller 102 is a computing device in charge of controlling thestructural elements of the three-dimensional shaping apparatus 100. Thecontroller 102 includes a CPU (central processing unit), a GPU (graphicsprocessing unit) or a MPU (micro-processing unit), for example. Thecontroller 102 reads and executes the programs stored in the storage 110to effectuate various functions, including a data processor 116 thatapplies desired image processes to color shaping data representingfeatures of the three-dimensional object 10.

The data processor 116 includes a data obtaining unit 118 that obtainscolor shaping data 150 (FIGS. 9A and 9B) using the image input I/F 104,a data correcting unit 120 that corrects the color shaping data 150, anda data generating unit 122 that generates intermediate data indicatingwhether the droplets 78 have been discharged and positions at which theyhave been discharged (hereinafter, referred to as discharge data).

The driver circuit 114 is an electric circuit electrically connected tothe controller 102. The driver circuit 114 drives the respective unitsand devices to carry out a shaping operation. In this embodiment, thedriver circuit 114 includes a discharge controller 124 for dischargecontrol of the discharge unit 80, and a curing controller 126 for curingcontrol of the curing unit 84.

The discharge controller 124 generates drive waveform signals foractuators of the discharge heads 88 and 90 based on the discharge datasupplied from the controller 102, and outputs the waveform signals tothe discharge unit 80. The curing controller 126 generates drive signalsfor the various energies to be applied, and outputs the drive signals tothe curing unit 84.

3. Operation of Three-Dimensional Shaping Apparatus 100

The three-dimensional shaping apparatus 100 according to this embodimentis structured as described thus far. Next, the operation of thethree-dimensional shaping apparatus 100 is described referring to theflow chart of FIG. 7, and FIGS. 8, 9A and 9B.

In Step S1, the controller 102 (data obtaining unit 118) obtains thecolor shaping data including 3D-CAD (computer aided design) data usingthe image input I/F 104. The color shaping data represents an originalcolored object having the same external appearance as thethree-dimensional object 10. In a case of a wire-frame model, the colorshaping data is a combination of shape model data representing thethree-dimensional frame of the three-dimensional object 10 and surfaceimage data representing images on the outermost surfaces 12 and 14. Thewire frame model is a non-limiting example of 3D visual presentations ofthe color shaping data. Instead, the surface model or solid model may beemployed.

In Step S2, the data generating unit 122 rasterizes the color shapingdata in the vector data format obtained in Step S1. Prior to the processin this step, the data generating unit 122 determines intra-frame colors(for example, white) and superimposes surface images on surfaces withinthe frames using the known texture mapping. Then, the data generatingunit 122 converts the original data into raster data suitable forthree-dimensional resolutions in the X, Y, and Z directions. Based onthe premise that rendering of data, even with changes in data format,has a substantially equivalent outcome, the converted data ishereinafter referred to as the “color shaping data” as before.

In Step S3, the controller 102 (data correcting unit 120) analyzes thecolor shaping data obtained in Step S1 to decide on necessity orunnecessity of the partition layer 26 and where to be positioned ifnecessary. Specifically, the data correcting unit 120 executesgeometrical computations using frame information (apexes and which onesof the apexes are connected) contained in the shape model data tocalculate the adjacent angles θ between the outermost surfaces 12 and14. The data correcting unit 120 further analyzes pixel values of thesurface image data to obtain the colors of the outermost surfaces 12 and14.

FIG. 8 is a schematic drawing, illustrating how to decide the positionof the partition layer 26. This drawing illustrates a virtual object 142rendered based on the color shaping data 150 (FIGS. 9A and 9B) in apredefined three-dimensional work region 140. As described earlierreferring to FIG. 3, the adjacent angle θ between the plane Q1PQ2constituting the outermost surface 12 and the plane Q1PQ3 constitutingthe outermost surface 14 is 90 degrees (θ=90 degrees). It is accordinglydecided that the partition layer 26 is disposed in vicinity of sides PQ1and PQ4.

Importantly, the partition layer 26 is disposed with a line segment OPpartly included therein, where “O” refers to the center of gravity ofthe virtual object 142. An outer endpoint Ro is a point on the linesegment OP more inward than an apex P by a certain distance (depth fromthe ridge 30). An inner endpoint Ri is a point on the line segment OPmore inward than the outer endpoint Ro by a certain distance (width ofthe partition layer 26).

The data correcting unit 120 executes similar computations for any otherapexes but the apex P and identifies the outer endpoints Ro and innerendpoints Ri in relation to these apexes. Then, the adjacent outerendpoints Ro or the adjacent inner endpoints Ri are successivelyconnected to decide a region where the partition layer 26 of FIG. 3should be disposed.

In Step S4, the data correcting unit 120 corrects the color shaping data150 rasterized in Step S2, and disposes the partition layer 26 inaccordance with the decision made in Step S3. This method of correctionis hereinafter described in detail referring to FIGS. 9A and 9B.

FIG. 9A is a drawing of pixel values constituting the color shaping data150 yet to be corrected, substantially corresponding to the renderingillustrated in FIG. 4A. This drawing illustrates, on its left side,continuous slice data 151 having the color channel of C (cyan). In thisdrawing, numbers in squares representing image regions are pixel values(8-bit gradation); “255” represents the highest gradation, and “0”represents the lowest gradation.

As is understood from the rendering of the continuous slice data 151,the pixel value corresponding to the first colored layer 20 is “c1”(first color), and the pixel value corresponding to the second coloredlayer 24 is “c2” (second color). The pixel value corresponding to theshaping base 16 is “0” (achromatic color), and the pixel valuecorresponding to the margin is “0” (colorless).

This drawing illustrates, on its right side, continuous slice data 152having the color channel of W (white). As is understood from therendering of this data, the pixel value corresponding to the firstcolored layer 20 is “0” (first color), and the pixel value correspondingto the second colored layer 24 is “0” (second color). The pixel valuecorresponding to the shaping base 16 is “255” (achromatic color), andthe pixel value corresponding to the margin is “0” (colorless).

The data correcting unit 120 updates the continuous slice data 151 byoverwriting the pixel values “c1” and “c2” corresponding to thepartition layer 26 with “0” and “0”, respectively. The data correctingunit 120 further updates the continuous slice data 152 by overwritingthe pixel value “0” corresponding to the partition layer 26 with “255”.

FIG. 9B is a drawing of pixel values constituting the color shaping data150 that has been corrected, that is, corrected shaping data 160,substantially corresponding to the rendering illustrated in FIG. 4B.This drawing illustrates, on its left side, continuous slice data 161having the color channel of C (cyan), and continuous slice data 162having the color channel of W (white).

In Step S5, the data generating unit 122 applies various image processesto the corrected shaping data 160 obtained in Step S4 to generatedischarge data for use in the discharge control for the droplets 78. Theimage processes may include halftone process including dithering,related color/different color plate division, dot size (droplet volume)layout, and process to constrain the number of droplets discharged, forexample.

In Step S6, the three-dimensional shaping apparatus 100 carries out theshaping operation based on the discharge data generated in Step S5.Specifically, the three-dimensional shaping apparatus 100, whilethree-dimensionally moving the mounting table 68 and the discharge unit80 relative to each other, sequentially stacks the unit layers includingthe modeling material 52 and the support material 54 along the Zdirection. The apparatus 100 successively performs [1] discharge of thedroplets 78 from the discharge unit 80, [2] flattening of the unit layersurfaces 56 using the flattening roller 82, and [3] curing of thedroplets 78 using the curing unit 84 for [4] growth of the multilayeredstructure 50, to complete the production of the multilayered structure50 as an intermediate shaped object.

In Step S7, the support material 54 is removed from the intermediateshaped object obtained in Step S6. Then, the three-dimensional object 10illustrated in FIG. 1 is finally obtained. The support material 54 maybe removed through a physical treatment or a chemical treatment suitablefor the properties of the support material 54. Examples of the treatmentmay include dissolving using water, heating, chemical reactions, washingunder water pressure, and irradiation of electromagnetic wave.

4. Effects Attained by Three-Dimensional Shaping Apparatus 100

As described so far, the three-dimensional shaping apparatus 100vertically stacks the unit layers on one another that include aplurality of different modeling materials 52 that enable colorreproduction of at least the first color and the second color to shapethe three-dimensional object 10. The three-dimensional object 10 shapedincludes: the shaping base 16 having the first outer surface(s) 18 andthe second outer surface(s) 22 adjacent to each other at the adjacentangle θ; the first colored layer(s) 20 formed on the first outersurface(s) 18 of the shaping base 16 and including a transparentmaterial colored in the first color, and the second colored layer(s) 24formed on the second outer surface(s) 22 of the shaping base 16 andincluding a transparent material colored in the second color.

The three-dimensional shaping apparatus 100 has the data obtaining unit118 and the data correcting unit 120. The data obtaining unit 118obtains the color shaping data 150 representing the original coloredobject including the shaping base 16, first colored layer(s) 20, andsecond colored layer(s) 24. The data correcting unit 120 corrects theobtained color shaping data 150 to interpose the opaque partition layer26 between the side surfaces of the first and second colored layers 20and 24 in the original colored object. The partition layer 26 has one ofthe first color, the second color, and an achromatic color with zerosaturation or very low saturation.

The three-dimensional shaping method using the three-dimensional shapingapparatus 100 includes the obtaining step (S1) of obtaining the colorshaping data 150 representing the original colored object, and thecorrecting step (S4) of correcting the obtained color shaping data 150.These technical features may allow the shaped three-dimensional object10 (FIGS. 1 to 4B) to maintain a satisfactory visual color quality whenobserved at different positions or through different angles.

[Additional Remarks]

This disclosure is not confined to the embodiment and the modifiedembodiment described thus far. It should be understood that thisdisclosure may be unlimitedly subject to any changes within the scope ofthe contents of this disclosure.

For example, the three-dimensional shaping apparatus 100 may be operableto set layout information on the partition layer 26. In this instance,the controller 102 obtains the layout information as instructed by anoperator's manipulation of the input unit 106, and generates thecorrected shaping data 160 based on the obtained layout information.This layout information contains specifics of the partition layer 26(for example, thickness, width, position, color) and/or criteria onwhether the partition layer 26 should be provided (for example,threshold θth, necessity or unnecessity of the partition layer 26).

In this embodiment, the data correcting unit 120 corrects the colorshaping data 150 converted into the format of raster data. This is,however, a non-limiting example of the data correction timing. Forexample, the multi-gradation data may be corrected subsequent to thehalftone process, or the vector data may be corrected prior to therasterizing process.

In this embodiment, the mounting table 68 and the discharge unit 80 maybe both movable members. Instead, one of the mounting table 68 and thedischarge unit 80 may be moved, with the other being immovably fixed.Further, the three directions of movement (X direction, Y direction, Zdirection) may be optionally combined.

This embodiment has described the three-dimensional shaping apparatus100 of inkjet type. This is, however, a non-limiting example of thisdisclosure. This shaping apparatus may be further applicable to fuseddeposition modeling, stereolithography, selective laser sintering,projection, and inkjet binder jetting.

What is claimed is:
 1. A three-dimensional shaping method, adapted forshaping a three-dimensional object by stacking unit layers on oneanother using a three-dimensional shaping apparatus, the unit layersincluding a plurality of different shaping materials that enable colorreproduction of at least a first color and a second color different fromthe first color, the three-dimensional object comprising: a shaping basehaving a first outer surface and a second outer surface adjacent to eachother at an adjacent angle; a first colored layer formed on the firstouter surface of the shaping base, the first colored layer including atransparent material colored in the first color; and a second coloredlayer formed on the second outer surface of the shaping base, the secondcolored layer including a transparent material colored in the secondcolor, the three-dimensional shaping method comprising: an obtainingstep of obtaining color shaping data representing an original coloredobject including the shaping base, the first colored layer, and thesecond colored layer; and a correcting step of correcting the colorshaping data obtained in the obtaining step to interpose a partitionlayer between a side surface of the first colored layer and a sidesurface of the second colored layer in the original colored object, thepartition layer being opaque and having an achromatic color with zerosaturation or very low saturation, wherein in the correcting step, thecolor shaping data is corrected so that the partition layer is formedalong a region where the side surface of the first colored layer makes asurface contact with the side surface of the second colored layer, andthe partition layer is formed so that at a position where the sidesurface of the first colored layer makes the surface contact with theside surface of the second colored layer, a light incident from anoutside of the first colored layer or the second colored layer isshielded and reflected from the partition layer to an opposite side withrespect to the partition layer.
 2. The three-dimensional shaping methodaccording to claim 1, in a step which is after the obtaining step orbefore the correcting step, further comprising a determining step inwhich a necessity or an unnecessity of disposing the partition layer isdecided.
 3. The three-dimensional shaping method according to claim 1,wherein the color shaping data comprises a combination of a shape modeldata representing a three-dimensional frame of the three-dimensionalobject and a surface image data representing images on an outermostsurface of the three-dimensional object.
 4. The three-dimensionalshaping method according to claim 2, wherein the color shaping datacomprises a combination of a shape model data representing athree-dimensional frame of the three-dimensional object and a surfaceimage data representing images on an outermost surface of thethree-dimensional object.
 5. The three-dimensional shaping methodaccording to claim 2, wherein the adjacent angle is calculated byexecuting geometrical computations using a frame information containedin a shape model data in the determining step, and the partition layeris provided only where the adjacent angle has a degree less than athreshold.
 6. The three-dimensional shaping method according to claim 3,wherein the adjacent angle is calculated by executing geometricalcomputations using the frame information contained in a shape model datain the determining step, and the partition layer is provided only wherethe adjacent angle has a degree less than a threshold.
 7. Thethree-dimensional shaping method according to claim 3, wherein thepartition layer is provided at an inner side with respect to theoutermost surface of the three-dimensional object at a position wherethe first colored surface makes the surface contact with the secondcolored layer, and the partition layer is formed in a shape whichextends from a place where the first outer surface of thethree-dimensional object and the second outer surface of thethree-dimensional object are adjacent to each other along a place wherethe first colored layer and the second colored layer are in contact witheach other.
 8. The three-dimensional shaping method according to claim4, wherein the partition layer is provided at an inner side with respectto the outermost surface of the three-dimensional object at a positionwhere the first colored surface makes the surface contact with thesecond colored layer, and the partition layer is formed in a shape whichextends from a place where the first outer surface of thethree-dimensional object and the second outer surface of thethree-dimensional object are adjacent to each other along a place wherethe first colored layer and the second colored layer are in contact witheach other.
 9. The three-dimensional shaping method according to claim1, wherein the partition layer has a lower light transmittance than thefirst colored layer and the second colored layer.
 10. Thethree-dimensional shaping method according to claim 2, wherein thepartition layer has a lower light transmittance than the first coloredlayer and the second colored layer.
 11. The three-dimensional shapingmethod according to claim 3, wherein the partition layer has a lowerlight transmittance than the first colored layer and the second coloredlayer.
 12. The three-dimensional shaping method according to claim 5,wherein the partition layer has a lower light transmittance than thefirst colored layer and the second colored layer.
 13. Thethree-dimensional shaping method according to claim 7, wherein thepartition layer has a lower light transmittance than the first coloredlayer and the second colored layer.